MarketWatch reports that Fed Chairman Jerome Powell said that bitcoin is lacking key ingredients that would make it a useful currency. As a result, the crypto currency is essentially more of a substitute for gold than the dollar.

“Crypto assets are highly volatile and therefore not really useful as a store of value. They’re not backed by anything. They’re more of an asset for speculation,” Powell said. “It is essentially a substitute for gold rather than the dollar,” he added.

Stable coins are “an improvement” over crypto assets, but their credibility comes from being backed by a sovereign currency, he said.

“Stable coins may have a role to play with appropriate regulation, but that role will not be to form the basis of a new global monetary system,” he said.

One day in the future, the Fed might develop a digital dollar, Powell said, but not until after a lot of careful review and acceptance by the American public and government.

It would be better for Congress to pass laws specifically authorizing the digital currency rather than for the Fed to use existing authority, he said.